1. Field of the Invention
The present invention relates to improvements in feller heads of the type used for felling trees.
2. Description of the Prior Art
There are many patents relating to felling heads. Generally, a felling head includes an upstanding frame adapted to be mounted at the end of a knuckle boom and is hydraulically operated and oriented. Grapple arms are mounted on the frame to engage and hold the tree to be cut, and a cutting device at the bottom of the frame cuts the trunk of the tree at the lowest possible point above the ground. One or more accumulator arms are provided on the frame for retaining the severed tree against the upstanding frame while the feller engages other trees.
In recent years, a circular saw having replaceable teeth has been increasingly utilized as the cutting device. However, since it is so near the ground in operation, especially as it is moved to engage the trunk of a tree, the circular saw is easily damaged. The circular saw can rotate up to 1200 r.p.m., and as the teeth hit an obstacle such as a boulder, they can easily shatter or otherwise be damaged.
The grapple arms are usually placed in the upper part of the frame and in the lower part of the frame near the cutting device. The accumulator arm or arms are provided near the midpoint of the frame. However, in view of the radius of the circular saw, the trunk of the tree, before being severed, is at a distance (at least the radius of the circular saw) from the frame. Thus, when the lower grapple reaches out and engages the tree to hold during cutting, the trunk can be damaged, especially if it is of small diameter.